1. Field of the Invention
As increasing knowledge is obtained concerning vitamin K dependent bone protein, referred to hereinafter as bone Gla protein (BGP) or .gamma.-carboxyglutamic acid containing protein, assays will be required having an enhanced sensitivity and specificity. That is, where antibodies are employed, it will be necessary that the antibodies be specific for the protein of interest and in particular defined regions of protein, having substantially different binding affinities between the protein of interest and regions thereof, and other proteins. The greater the binding affinity, all other things being equal, the greater the sensitivity of the assay.
2. Description of the Prior Art
An abstract of a paper by Price, et al., was published in June, 1979, for the meeting of the American Society for Bone and Mineral Research. Price and Nishimoto, Proc. Natl. Acad. Sci. USA 77: 2234-2238 (1980) and Price, et al., J. Clin. Invest. 66: 878-883 (1980) both describe a radioimmunoassay utilizing antibodies and labels derived from the intact BGP molecule. Deftos, et al., Calcif. Tissue Int., 34: 121-124 (1982) describes the clinical measurement of changes in BGP during treatment of bone disease. The references cited in the aforementioned references should also be noted. Copending application Ser. No. 246,972 suggests the use of fragments of BGP of at least 20 amino acids as reagents in immunoassays for BGP.